Telephone-transmitter.



Patented Dec. 6, 1910.

J. SPARKS.

TELEPHONE TRANSMITTER.

APPLIUATION FILED MAR. so. 1910.

l To all whom it may concern:

UNITED -sTATEs PATENT oEEioE.

JOHN SPARKS, 0F KIMBERLY, CALIFORNIA.

TELEPHONE-TRANSMITTER.

Be it known that I, JOHN SPARKS, lcitizen of the United States, residing at Kimberly, in the county of Shasta and State of California,haveinvented new and useful Improvements in Telephone-Transmitters, of which the following is a specification.

My invention relates to telephone transmitters, and pertains especially to whatI term a pneumatic microphone transmitter.

The object of the invention is to provide a simple, practical means for intensifying the sound vibrations s0 as to enable heavier battery currents' to be used, and therefore greater electro-motive force and current in the secondary or receiver circuit.

The invention consists of the parts and the construction and combination of parts as hereinafter more fully described and claimed, having reference to the accompanying drawings, in which- Figure 1 is a section through the invention with the circuits represented diagrammatically. Fig. 2 is a plan view of the statinarycarbon disk showing the pockets of granular material.

A is a sound-box or base or a metal case o en at the back, and provided. with a telep one mouth-piece 2 and metal diaphragm 3. -At the back and secured to the case by a yoke or open web 4 is a cylinder 5 or valve chest with its center line of bore directly in line with the center of the diaphragm. The cylinder 5 has an inlet opening 6at the top midway yof its length for the admission 0E compressed air from any suitable source of supply; and opposite and t0 either side of port 6 are two pairs of slits 7-8910 at the bottom forming outlet ports, each pair 7-1-8 and 9-1'0 of slits at either end leading into a respective small chamber with au 0utlet 11-12, these outlets 11-12 connected loyl a respective tube 13-14.- with the microphone B, as will be shortly described.

Within the cylinder 5 and accurately fitted and free tOvibrate there 'is a balanced valve 15 of the spool type made of metal or other suitable substance. This valve is connected to the diaphragm by a small bolt or rod 16 and can be s0 'adjusted that when normal its heads ateither end will not quite The vmicrophoneB consists of a metal cyl- Patented Dec. 6, 1910.

inder 17 of short length and rather large diarneter, with an internal annular flange 18 receiving a carbonring 19 driven in tightly and makingelectrical connection with the cylinder 17. The ring 19 has six, more or less, circular pockets at either side made by cementing a small ring 20 of floss or yarn to the face. The pockets are filled Vwith granular particles of carbon 21 against which, and on either side of the carbon ring 19, bear the vibrating carbon disks 22 which are attached to the metal diaphragms 23 and insulated electrically from the cylinder 17 except through lthe stationary carbon ring 19 and the granular particles of carbon 21. The diaphragms 23.and carbon disks 22 are tied together mechanically by a piece of vulcanized fiber 24 or other non-conducting material which passes through the center of the carbon ring 19 and is free to vibrate; a screw 25 passing through a hole in each dia phragm and disk into a female thread in the ber to complete the tie."

Each diaphragm 23 and its disk 22 are free to vibrate in a respective chamber 26 formed between a diaphragm and a head 27 of cylinder 17, and each chamber 26 is connected through a port 28 `with a respective tube or air duct 13-14. Holes 29 are bored through the walls of the cylinder 17 into the disk chambers 26 inside the diaphragm 23 to communicate with the atmosphere. The diaphragms rest on a rubber ring 30 on a shoulder formed by the larger bore of the cylinder 17 which receives the heads. The ports 28 are at the center of each of the heads and are rounded off at their edgesto insure easy admission of air from the. valve I chest 5.

Each diaphragm 23 is connected by a wire 31 passing through an insulated hole in the walls of the cylinder 17'; and each wire connects through a separate battery 32 with the primary winding 33 of a separate Iinduction coil, thence returning to thevbody of the c linder by wire 34. to make connection with the carbon ring 19. The batteries 32 are so connected that 'the current passes through the primary windings of thecoils in opposite directions. The secondary windings 35 of the coils are `connected in series, thence out over the line 36 and through the receiver 37 at the other end.

l' In operation,` af-pressure of air through s port 6 at anywhere abovel atmospheric presy sure entering vthe valve chest 5, withthe valve' 15 in'normaf'gor vertical position, will flow down against each head of the balanced valve through the orts 8'- -9 which are partly un- 'coveredby t e heads of the valve, and `out throughk the exhaust'ports 7-10 which are also left partly uncovered. At the same time there will be pressureapplied oneach of the diaphragms 23 in the microphone, but being equalized, they will balance,- and no 'disturbance of the electrical resistance .of the transmitter` will' result, and therefore, -no sound in' the receiver; but any movement of the diaphragm 3 of the mouth-piece will cause a movement of the valve 15 in the air chest -5, which will uncover,fmore'or less, one or valve 15 to close, more or less, both the ports l diaphragm chamber 26 to the le the other ofthe supply ports v8- 9 and cover, more'or'less one'or the'other of the correspending exhaust orts 7"10: Of course, the .vibrations of t ediaphragm 3 due-to the talking'into the mouth-piece 2 willresult in the very rapid reciprocationor flutter ofthe valve l.15, andof coursethe reac-` .tion on the diaphragms- 26 will be very rapid. That is to say, a movement of diaphragm 3'toward valve chest 5 will cause 9 and 7. This will cause arise in ressure in through tube 13 and port 28 and result'in' compressing thejgranular carbon particles 2l on that -side of the fixed carbon disk 19. 'Atthe same time pressure: isreduced in the opposite chamber 26 and relieving the pressure on the-carbon particles on that side.- Simultaneously with these movements an increase of current dueto the compression of the loose carbon on the left will flow from the right-hand batte 32 through its primary coil 33, While the ow of current throughthe other primary willbe decreased. The result will be a strong impulse of currentthrou 'h' the secondaries of the coils in the -same irection, and a movement` of the diaphragm in the receiver at the end of the line. When the diaphragm 3` vibrates tothe right, or awayfrom the valve chest `5, theaction is reversed. It is naturally understood that lthese vibrations occur veryrapidly and the larger diaphragm of the microphones and varying the electrical resistance and cause waves 'of current to flow and vibrate in the receiver, reproducing sound waves made at the mouth-piece.

41:3 j, f When using the device `the air pressure is 4 cenetant.A through the inlet 6, and this air ,pressuie'inay beanywhere from one ounce to one/hundred? pounds, more. o r less.

The object of applyingcompressed air to the transmitter isfto obtain -an increase in .stren Ath of the vibration of the microphone,

enabling heavier batterycurrents to be used and therefore-'greater electro-motive force andcu ent in the secondaryor receiver thusl described invention, what I claim' and desire to secureby Letters Pat# I ent fjl. The combination with a An iouth-I'iiece havin"A a diaphragm, of a valve-chest to receive uid under pressure, a balanced-valve. operable in the valve chest and connected to and` movablelwiththe mouth-piece diaphragm, and mechanism controlled by the valve andexposable to the'iiuid pressure for electrically reproducing sonorous vibrations of thediaphragm.'

2. The `combination of a mouthieee, a

mouth-l iece diaphragm, a valve c est',1'.a-

balance valve therein'connected with said diaphragm, said valve chest connected witha source of Iliiidlfpressure supply, mechanism including suitable circuits. and receivsonorous vibrations, and means y lwhich of said valve.

3. The combination ported ixed carbon disk, vibrating; carbons on v each jsidethereof, diaphragme carrying l. said vibrating carbons, connections between the vibrating carbens whereby they vibrate in unison, a granular carbonbody between each vibrating carbon' andthe xed carbon, a telephone mouth-piece and diaphragm,

ing `mechanism for electrically re roducing` said mechanism lis operated by the vibration 'of a suitably vsup-l pneumatic meanscontrolled by the mouthpiecediaphragm, for actuating 'the firstinentioned diaphragms, and electrical mech` anism` controlled by the vibrations of said rst-mentioned diaphragms.

- 4; The combination of a suitablyl supported fixed carbon disk, vibrating carbons oneach side thereof, diaphragms carrying said vibrating carbone, connections'betwe'en the vibrating carbons whereb the vibrate in unison, a granular carbon odyl etween each j vibrating carbon and the fixed carbon, said diaphraig'ms'vibrating inuid chambers, means or. alternately increasing vthe pressure. in one chamber and decreasing ,the

pressurein the other, and means for alter-y nately reproducing the avibrations of ysaid diaphragms.

5. The combination of a suitably" supported 'fixed carbon disk, `vibrating carbonsy on each side thereof, diaphragms carrying said vibrating carbons, connections between the vibrating carbons whereby they vibrate Avibrate, a valve chest havin piece, a diaphra m actuated chest, connections between 4the and valve, a receiver. and electrlcal connec-i tions between the receiver a l phragms in said Huid chamber nd said dia- 10 In testimony lwhereof I have hereunto set my hand in the presence of two subscribing wltnesses.

Witnesses CHARLES EDELMAN, HENRY L. PURDY.

JOHN sPiuzKs.l 

